1. Field of the Invention
The present invention relates generally to surface light source devices, and particularly to a surface light source device with light emitting diodes (LEDs).
2. Description of related art
With features of long-term reliability, small size, environment friendliness and low power consumption, presently, LEDs are widely used as backlight source of liquid crystal display (LCD) devices, automobiles lights, and common luminous sources and so on.
LEDs are generally used in a surface light source device as a backlight source in an LCD device. The surface light source device comprises a light guide plate and a plurality of LEDs attached to the light guide plate. According to positions where the LEDs are mounted on the light guide plate, the surface light source devices are generally categorized to edge lighting mode and bottom lighting mode. In the edge lighting mode, the LEDs are attached to an edge of the light guide plate. In the bottom lighting mode, the LEDs are attached to a bottom of the light guide plate. With the development of electronic industry, large area light source with large light guide plate is needed. However, the surface light source device with the edge lighting mode is not suitable for large light guide plate to provide sufficient light. The surface light source device with the bottom lighting mode suit for large light guide plate to provide sufficient light, but in this mode, more LEDs are needed to emit light, which inevitably increase cost thereof.
What is needed, therefore, is a surface light source device with LEDs having a large light area and a low cost.